package Set;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class Main07 {   public static void main(String[] argv)
        throws Exception {
    List stuff = Arrays.asList(new String[] { "a", "b" });
    List list = new ArrayList(stuff);
    list = Collections.unmodifiableList(list);
    try {
        list.set(0, "new value");
    }
    catch (UnsupportedOperationException e) {
    }
    Set set = new HashSet(stuff);
    set = Collections.unmodifiableSet(set);
    Map map = new HashMap();
    map = Collections.unmodifiableMap(map);
    System.out.println("集合现在是只读");
}

}
